Go for a hike to the Flatirons On the weekend there are free shuttles to various trails about Boulder: https://www.bouldercoloradousa.com/outdoors/hiking/hiker-shuttles/
Take a tour of the Celestial Seasonings tea factory
Saturdays 8AM-2PM
Visit one or some of the many breweries around Boulder
https://www.bouldercoloradousa.com/outdoors/water-recreation/tubing/